US4443796A - Doppler radar - Google Patents

Doppler radar Download PDF

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Publication number
US4443796A
US4443796A US06/262,800 US26280081A US4443796A US 4443796 A US4443796 A US 4443796A US 26280081 A US26280081 A US 26280081A US 4443796 A US4443796 A US 4443796A
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United States
Prior art keywords
cavity resonator
doppler radar
facing
radar according
opening
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Expired - Fee Related
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US06/262,800
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English (en)
Inventor
Jorg Muller
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Siemens AG
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Siemens AG
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Assigned to SIEMENS AKTIENGESELLSCHAFT reassignment SIEMENS AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MULLER, JORG
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S13/56—Discriminating between fixed and moving objects or between objects moving at different speeds for presence detection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G01S7/032—Constructional details for solid-state radar subsystems
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/247—Supports; Mounting means by structural association with other equipment or articles with receiving set with frequency mixer, e.g. for direct satellite reception or Doppler radar

Definitions

  • the invention relates to a doppler radar, including two substantially prismatic cavity resonators having substantially the same dimensions and being connected to each other by means of a wall common to both cavity resonators, an oscillator diode being disposed in the first cavity resonator and a receiving diode being disposed in the second cavity resonator.
  • a corresponding doppler radar which is suitable for speed measurement or for the detection of motion is known from the article by M. W. Hosking "Microwave Intruder Alarm” from Wireless World, July 1977, Page 36 et sec.
  • That device includes two prismatic cavity resonators which have substantially the same height, width and length, are rigidly connected to each other at one of their longitudinal sides, and have end faces aimed at the object to be measured which are open.
  • a Gunn diode is provided for exciting oscillations
  • a Schottky diode is provided in the second cavity resonator for frequency mixing.
  • the waves radiated due to the open end face of the first cavity resonator are reflected by a moving object with a different frequency because of the doppler effect.
  • the doppler frequency is obtained by heterodyning the transmitting frequency with the return frequency, and is fed to further evaluation means.
  • the doppler radar should also be economical to produce for different transmitter powers.
  • a doppler radar for measuring objects comprising a first and a second substantially prismatic cavity resonator each having an end face pointing or facing the object to be measured and each having substantially equal dimensions, a common wall connecting the cavity resonators to each other, an oscillator diode disposed in the first cavity resonator, a receiving diode disposed in the second cavity resonator, the end of the first cavity resonator facing the object to be measured being closed and the end of the second cavity resonator facing the object to be measured being open, and the common connecting wall having an opening formed therein.
  • the waves generated in the first cavity resonator are not radiated directly in the direction of the object to be determined but are coupled through the opening made in the connecting wall into the second cavity resonator and radiated through the open end face of the second cavity resonator. Due to the high percentage of radiated power which acts on the receiving diode disposed in the second cavity resonator, its characteristic is well modulated. An output signal which is considerably larger than in the previous state of the art is obtained. Depending on the size of the opening in the connecting wall, the radiated power can be further adjusted.
  • the common connecting wall has a reduced thickness region formed therein in the vicinity of the opening.
  • the reduced thickness region of the wall is between 0.3 and 1.5 mm thick.
  • the common connecting wall has an additional counterbore formed therein in the vicinity of the opening having a larger cross-sectional area than the opening.
  • the first cavity resonator has another end face pointing away from the object opposite to the end facing the object, the opening being spaced from the other end by a distance of (2n+1). ⁇ /4, especially ⁇ /4, where ⁇ is the wavelength of oscillations excited in the first cavity resonator and n is an integral number starting from 0.
  • the opening has a diameter of between one-half of and the full height of the common connecting wall.
  • a dielectric insert formed of a material having a dielectric constant greater than that of air, the insert being disposed in at least the first cavity resonator.
  • the first cavity resonator has another end opposite to the end facing the object, and the dielectric insert is approximately prismatic and has a rectangular surface corresponding in dimensions to one of the ends of the first cavity resonator.
  • a dielectric insert disposed in the first cavity resonator at the end thereof facing the object.
  • the dielectric insert is formed of plastic such as polyvinyl chloride or ceramic.
  • the second cavity resonator has another end face pointing away from the object opposite to the end facing the object, and the metal part is spaced at a distance from the other end of ⁇ /2, where ⁇ is the wavelength of oscillations.
  • the length of the metal post prodruding into the second cavity resonator is at most half the height of the second cavity resonator.
  • a cover being cold-welded to the first cavity resonator closing off the end thereof facing the object.
  • the doppler radar according to the invention is preferably used as a proximity switch or a speed measuring device.
  • FIG. 1 is a diagrammatic perspective view of an embodiment of a doppler radar according to the invention.
  • FIG. 2 is a cross-sectional view taken along the line II--II in FIG. 1, in the direction of the arrows.
  • the embodiment example shown therein includes a first cavity resonator 1, in which an oscillator diode such as a Gunn-diode is disposed.
  • the Gunn-diode is not shown in the figure for reasons of clarity.
  • a second cavity resonator 2 in which a receiving diode, such as a Schottky diode is located, but is likewise not shown in the figure.
  • the cavity resonators 1 and 2 are separated by a connecting wall 3 in which an opening, such as a circular opening 4, is located.
  • the end face of the first cavity resonator 1 which points toward the object 5 that is normally moving, is closed off, such as by means of a cover 6.
  • the corresponding end face of the second cavity resonator 2 is open.
  • the resonators 1 and 2 may have the same dimensions as each other and are prismatic in the example shown, the end faces pointing toward the object 5 having a somewhat larger cross-section than the opposite end faces.
  • other resonator forms also suitable for generating microwaves can be used.
  • FIG. 2 shows a horizontal cross section through the center of the embodiment shown in FIG. 1.
  • the same reference symbols as in FIG. 1 are used in FIG. 2.
  • the oscillator diode 9 is disposed in the first cavity resonator 1 and the receiving diode 10 is disposed in the second cavity resonator 2.
  • a counterbore 8 formed in the vicinity of the hole 4 in the connecting wall 3 serves for better power transmission between the two resonators.
  • Fine control of the transmitter power is possible by means of a metal post 11.
  • the post 11 has an axis which is perpendicular to the plane of the drawing of FIG. 2 and it is disposed in the second cavity resonator 2 in such a manner that its length projecting into the resonator 2 is variable.
  • the metal post 11 can be constructed as a screw, for instance.
  • the overall length of the doppler radar can be shortened by means of a dielectric insert 12.
  • the material suitable for the insert 12 may be any dielectric material with a dielectric constant larger than that of air, for instance plastics such as polyvinyl chloride.
  • the cavity resonator 1 can be operated at different frequencies in a simple way and without great effort for changing. If a first cavity resonator 1 is used which is closed according to the invention, the dielectric insert 12 can be exchanged in a simple manner by opening the cover 6. It is particularly advantageous to choose the dielectric insert so that a temperature-related frequency change of the resonator 1 is compensated, i.e.
  • a suitable ceramic material is (Zr x Ti y Sn z ) O 4 for example, where the sum of the three subscripts x, y and z is two.
  • the radiated power of the doppler radar can be roughly set by the choice of the diameter of the opening 4.
  • the radiated power is 20 dB smaller for a hole diameter which corresponds to one-half of the height 13 of the connecting wall 3, than if an opening 4 is used having a cross section which corresponds to the entire height 13 of the connecting wall 3.
  • the transmitted power can be increased by reducing the wall thickness of the connecting wall 3.
  • the opening 4 is advisable to locate the opening 4 at a distance of (2n+1) ⁇ /4 and in particular ⁇ /4, from the rear wall 16 of the first cavity resonator 1.
  • the distance between the receiving diode 10 and the rear wall of the second cavity resonator 2 should be chosen correspondingly, and particularly should likewise be ⁇ /4.
  • the metal post 11 serving for fine control of the transmitter power can be disposed in the center of the second cavity resonator 2, i.e. at a distance of ⁇ /2 from the rear wall, for instance.
  • the transmitted power can be lowered, for instance, by 15 to 20 dB as compared to the maximum power, with a screw which can be turned up to one-half the height 13 of the resonator 2 into the resonator 2.
  • the receiving diode 10 receives a considerably larger share of the transmitted power if the first resonator is closed and the connecting wall 3 is provided with an opening 4. As compared to the arrangement known from the state of the art without an opening 4 and with the first cavity resonator open. The sensitivity of the doppler radar is therefore considerably improved.
  • the required opening area of the doppler radar is reduced by one-half in spite of the high sensitivity, which is a great advantage for numerous applications.
  • cavity resonators which oscillate in the range between 1 and 200 GHz can be used where an avalanche propagation-time diode (IMPATT diode) is advantageously used as the transmitting diode instead of a Gunn diode for very high frequencies.
  • IMPATT diode avalanche propagation-time diode
  • a corresponding doppler radar is normally operated in the frequency range between 9.3 to 10.7 GHz.
  • the radar can be used for detecting any moving objects, such as people, and can therefore be used as a burglar alarm or proximity switch. Use as a speed measuring device, such as for measuring the velocity of vehicles, is also possible.
  • Diameter of the opening 4 the wall height 13: 10.3 mm
  • irradiated power is in the order of magnitude of 1 mW.
  • the signal of the Schottky diode used as the receiving diode 10 is amplified by 60 dB by means of a three-stage, low-noise amplifier and is subsequently evaluated.
US06/262,800 1980-05-23 1981-05-12 Doppler radar Expired - Fee Related US4443796A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3019887 1980-05-23
DE3019887A DE3019887C2 (de) 1980-05-23 1980-05-23 Dopplerradar

Publications (1)

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US4443796A true US4443796A (en) 1984-04-17

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EP (1) EP0040818B1 (de)
DE (1) DE3019887C2 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4495499A (en) * 1981-09-08 1985-01-22 David Richardson Integrated oscillator-duplexer-mixer
US4731611A (en) * 1983-06-21 1988-03-15 Siemens Aktiengesellschaft Stripline doppler radar
US5511238A (en) * 1987-06-26 1996-04-23 Texas Instruments Incorporated Monolithic microwave transmitter/receiver
EP0799428A1 (de) * 1994-12-19 1997-10-08 The Regents Of The University Of California Pulsradar mit suchlaufentfernungsgatter
US5784021A (en) * 1996-01-25 1998-07-21 Cobra Electronics Corporation Noiseless radar detector

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3041574C2 (de) * 1980-11-04 1985-12-05 Siemens AG, 1000 Berlin und 8000 München Dopplerradar
DE3213335C2 (de) * 1982-04-07 1986-06-05 EMS Elektronik-Meßtechnik Dipl.-Ing. Leo Schmidt GmbH, 1000 Berlin Vorrichtung zur Erkennung von Meßobjekten aus unterschiedlichen dielektrischen Materialien
FR2574923B1 (fr) * 1984-12-19 1987-12-24 Maury Louis Fusee perfectionnee a detection de proximite pour projectiles

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2283935A (en) * 1938-04-29 1942-05-26 Bell Telephone Labor Inc Transmission, radiation, and reception of electromagnetic waves
US2433368A (en) * 1942-03-31 1947-12-30 Sperry Gyroscope Co Inc Wave guide construction
US2853687A (en) * 1953-08-11 1958-09-23 Harold E Weber Waveguide attenuators
US3122740A (en) * 1957-01-10 1964-02-25 Admiral Corp Velocity determining device
US3624555A (en) * 1970-03-02 1971-11-30 Johnson Service Co Microwave cavity oscillator
US3745573A (en) * 1963-09-24 1973-07-10 Us Navy Proximity fuze circuit
US3805262A (en) * 1972-07-03 1974-04-16 Johnson Service Co Transmission antenna mixer doppler motion detection
US4042934A (en) * 1975-06-05 1977-08-16 Radar Control Systems Corporation Doppler radar module employing coupled rectangular waveguides

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1573300A (en) * 1977-03-09 1980-08-20 Aei Semiconductors Ltd Microwave oscillators

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2283935A (en) * 1938-04-29 1942-05-26 Bell Telephone Labor Inc Transmission, radiation, and reception of electromagnetic waves
US2433368A (en) * 1942-03-31 1947-12-30 Sperry Gyroscope Co Inc Wave guide construction
US2853687A (en) * 1953-08-11 1958-09-23 Harold E Weber Waveguide attenuators
US3122740A (en) * 1957-01-10 1964-02-25 Admiral Corp Velocity determining device
US3745573A (en) * 1963-09-24 1973-07-10 Us Navy Proximity fuze circuit
US3624555A (en) * 1970-03-02 1971-11-30 Johnson Service Co Microwave cavity oscillator
US3805262A (en) * 1972-07-03 1974-04-16 Johnson Service Co Transmission antenna mixer doppler motion detection
US4042934A (en) * 1975-06-05 1977-08-16 Radar Control Systems Corporation Doppler radar module employing coupled rectangular waveguides

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Article by M. W. Hosking "Microwave Intruder Alarm" from Wireless World, Jul. 1977, p. 36.
Article by M. W. Hosking Microwave Intruder Alarm from Wireless World, Jul. 1977, p. 36. *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4495499A (en) * 1981-09-08 1985-01-22 David Richardson Integrated oscillator-duplexer-mixer
US4731611A (en) * 1983-06-21 1988-03-15 Siemens Aktiengesellschaft Stripline doppler radar
US5511238A (en) * 1987-06-26 1996-04-23 Texas Instruments Incorporated Monolithic microwave transmitter/receiver
EP0799428A1 (de) * 1994-12-19 1997-10-08 The Regents Of The University Of California Pulsradar mit suchlaufentfernungsgatter
EP0799428A4 (de) * 1994-12-19 1998-03-11 Univ California Pulsradar mit suchlaufentfernungsgatter
US5784021A (en) * 1996-01-25 1998-07-21 Cobra Electronics Corporation Noiseless radar detector

Also Published As

Publication number Publication date
DE3019887A1 (de) 1981-12-03
EP0040818B1 (de) 1984-10-17
DE3019887C2 (de) 1983-12-01
EP0040818A1 (de) 1981-12-02

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